Type C to HDMI Adapter

If your laptop is 4 K or 5K, but your external monitor is 1080 P or 2 K, please lower the resolution of your laptop to the same resolution as your external monitor.

Apple icon–>System Preferences–>Displays–>Arrangement–>Mirror Displays, then go back to “Displays” option–>“Optimize For” your HDMI monitor–>Scale–>”Larger Text” (such as 1920*1080) to fit for your external monitor, disconnect then connect the hub to try again.